I was similar; an embedded C++ engineer moving into web dev to get a project off the ground.

If you're going to write a modern web frontend like Next and Tailwind (which I agree is the right call) then I think continuing to use Typescript for your backend makes sense for sheer development velocity. Like https://github.com/t3-oss/create-t3-app

I'd advise against Heroku compared to hosts like Vercel, Railway, Planetscale, etc.